1. Tor D.Wager, James R. Killing, Edward E. Smith, Alex Sokolik, Kenneth L. Casey, Richard J. Davidson, Stephen M. Kosslyn, Robert R. Rose & Jonathan D. Cohen Presented by Javier Granados-Samayoa

2.  Pain can be modulated by attitudes and beliefs  Placebo Analgesia: reduction of pain through the belief that an inert treatment has analgesic properties  Some suggest the placebo effect can be attributed to response bias  An opioid antagonist reverses the placebo effect  Information processing mechanism not known

3.  Hypothesis: placebos create expectation of pain relief, which inhibits activity in pain processing areas

4.  Participants: n= 23  Procedure: - Applied cream to forearm and told them cream was either an analgesic or control - 1 second cue was “Get Ready” - 1-16 seconds of anticipation - 20 seconds of heat - 4 seconds of rest - 4 seconds to rate intensity - 40-50 seconds of rest

5.  Areas in the right and left dorsolateral prefrontal cortex (DLPFC) were more active in anticipation of pain for the placebo condition compared to control condition

6.  DLPFC activation correlated with activation in the periaqueductal grey area during anticipation of pain in placebo condition compared to control condition

7.  There was reduced activity in pain processing areas, predominantly in the late heat period (insula & thalamus), in the placebo condition compared to control condition

8.  PFC generates and maintains expectations about pain, which influence activity of pain processing areas  PFC activity triggers opioid release which inhibits afferent pain fibers  Late decreases in pain processing area activation may reflect cognitive reappraisal of pain, which may lead to reduced emotional significance and experience of pain

9.  Future Direction: Further examine the role of the DLPFC in the placebo effect (opioid release vs. attention)

10.  Strengths: - good control condition - experimental design allows for distinction between different pain periods - had different pain manipulations  Limitations: - cannot distinguish what the role of the PFC is in the placebo effect - did not use different placebo conditions  can lead to different results (Blackwell, Bloomfield & Buncher, 1972)

11. Questions?